Fluid pressure operated disk brake for the landing wheels of aircraft



BUTLER H. FLUID PRESSURE OPERATED DISK BRAKE FOR THE LANDING WHEELS OF' AIRCRAFT Feb. 13, 1951 Filed Sept. 14, 1946 Feb. 13, 1951 H. J. BUTLER 2,541,031

FLUID PRESSURE oPERATEn msx BRAKE EoR TRE LANDING WHEELS oF AIRCRAFT Filed Sept. 14, 1946 5 Sheets-Sheet 2 Feb. 13, 1951 H 1 BUTLER 2,541,031

FLUID PRESSURE OPERATED DISK BRAKE FOR THE LANDING WHEELS 0F AIRCRAFT Filed Sept. 14, 1946 5 Sheets-Sheet 3 Feb. 13, 1951 2,541,031

Y H. J. BUTLER FLUID PRESSURE OPERATED DISK BRAKE FOR THE LANDING WHEELS OF' AIRCRAFT- Filed Sept. l4, 1946 5 Sheets-Sheet 4 Feb. 13, 1951 H. 1. BUTLER 2,541,031

ELUD PRESSURE OPE-RATED DISK BRAKE EOE TEE LANDEN@ WHEELS oF AIRCRAFT Filed Sept. 14, 1946 5 Sheets-Sheet 5 Patented Feb. 13, 1951 FLUID PRESSURE OP FOB THE LANDING Henry James Butler, Sut

assigner to Dunlop Ru county of London, England,

ERATED DISK'BRAKE WHEELS OF AIRCRAFT ton Coldiield, England, bber Company Limited, 'a British company Application September 14, 1946, Serial No. 697,014 In Great Britain December 3, 1945 8 Claims. (Cl. 188-152) My invention has reference to improvements in brakes and is concerned more particularly though not exclusively with brakes for the landing wheels of aircraft and has for its object to provide a brake which is light in weight and which has a relatively large area of braking surface and in which provision is made for facilitating the dissipation of the heat which is generated during a braking operation so as to provide for a cool running brake.

The wheel and brake mechanism of my invention comprises a wheel, radially spaced coaxial inner and outer annular brake discs engaging with said wheel to be rotated thereby, said discs being capable of limited axial displacement relative to said wheel, non-rotatable friction members disposed adiacent opposite surfaces of the discs and adapted to contact at any moment only a portion of the braking area of said discs, and operating means co-acting with said non-rotatable members for effecting frictional engagement between said discs and said friction members.

The invention will now be described with particular reference to the accompanying drawings which illustrate the invention in its application to brakes for use with an aircraft landing wheel of generally known construction, and which brakes are adapted for hydraulic actuation.

In the drawings:

Figure l is a side elevation of an aircraft landing wheel incorporating a construction of brake in accordance with the invention.

Figure 2 is a transverse sectional view on an enlarged scale of part of the wheel and part of the brake as illustrated in Figure 1.

Figure 3 is a view generally similar to Figure 2 but illustrating another construction of brake in accordance with the invention.

Figure 4 is a side elevation of an aircraft landing wheel incorporating a further construction of brake in accordance with the invention;

Figure 5 is a fragmentary view in transverse section on an enlarged scale of part of the wheel and the brake illustrated in Figure 4.

Figure 6 is a side elevation illustrating somewhat diagrammatically yet another construction of brake in accordance with the invention and Figure 'l is a side elevation also illustrating somewhat diagrammatically still another construction of brake in accordance with the inven` tion.

In the drawings like numerals of reference in-.jl

dicate similar orv analogous parts in the several* views.

Referring first to the embodiment of the invention as illustrated in Figures 1 and 2.

`outer walls of which have The outer series of slottedbrackets 9 accommodate complementary projections 'Illa associated with the outer periphery of anannular brake disc I0 of a truncated triangular shape in cross section the said projections Illa being capable of axial movement within the slots in their respective brackets 9.

The inner series of slotted brackets: 9a accommodate in a like manner projections IIa associated with the inner periphery of an inner annular brake disc II which also is of a truncated triangular shape in cross section the sides of the inner annulus II conforming to the sides of the outer annulus I0 with the inner annulus I I constituting the base end of the truncated triangle.

The inner periphery of the outer annulus I0 is spaced radially from the outer periphery of the inner annulus II.

Bolted to the back plate I2 carried by a wheel leg I3 of an aircraft is a spider or support Il having three equidistantly spaced arms Ila. Adjacent to the end each arm I 4a of the spider Il is provided with a hole through each of which is passed the outwardly directed portion of a pin I5 having a head I5a on the inwardly directed end thereof. 'I'he Shanks of these pins I5 pass through the space I6 between the inner and outer annular brake discs IIJ and II respectively. The heads I5a of the pins I5 are seated in recesses I la, Fig. 2, in cup shaped members I1 which are filled withhydraulic fluid. These cup shaped members I'I are enveloped by cup shapedsleeves I8 having inwardly directed projecting portions I 8a adapted to work within the cup shaped members II. The acting faces of the sleeves I8 are in contact with the adjacent faces of brake pads I9a presented to the annular brake discs I0 and I I. Similar brake pads I9b are interposed between the outwardly directed faces of the annular brake discs I0 and I I respectively and the adjacent faces of the arms Ida of the spider It.

Each of the brake pads I9a and I9b is made in two parts so as to facilitate initial assembly and replacement and each hydraulic assembly is held together by its pin I 5 and a nut 20 which engages the threaded and projecting outer end of the pin I5.

Sealing rings 2| are interposed between the cup shaped members I1 and the walls of the sleeves |8 and sealing rings 22| and cover plates 222 held in position by split rings 22 are associated with the projecting portions |8a of the said sleeves I8. The spaces between the respective sleeves I8 and the cup shaped members I1 are filled with liquid and are in communication with the pressure lines by way of axial bores |5b in the pins Il.

-The open ends of the sleeves I8 are enclosed and gripped frictionally by envelopes 23 having corrugated bottoms. vThe corrugation of the bottoms of the envelopes 23 permits of a slight flexing of thesaid envelopes when relative displacevment takes place between the sleeves I8 and cup shaped members I1 on the introduction of fluid pressure into the space between these members. Thus when the pressure is relieved the envelopes 23 return to their initial position and draw the sleeves I8 with them so that the said envelopesv act as return springs.

Thel frictional grip between the envelopes and the sleeves I8 also permits of automatic adjustment of the positions of the friction pads |9a to compensate for wear of the friction surfaces. This takes place in the following manner: As

` wear of the pads I9a, |9b takes place the amount of travel of the pads I9a when the brakes are applied increases and consequently the degree of flexing of the envelopes 23 also increases. When this 'exceeds a certain value the force required to produce further flexing will be greater than that required to cause the sleeves I8 to slip in the envelopes 23 and the sleeves will, therefore, slip until the pads and annular braking surfaces are in frictional contact. When the braking pressure is relieved the pads will be withdrawn only by an amount corresponding with the movement of the envelopes on their return to their unstressed state, and the distance between the friction surfaces of the pads will thus reniain i constant.

It will be appreciated that during a braking operation braking pressure is not exerted continuously on the whole of the annular braking surfaces III and II but only at the three equidistantly spaced positions so that a part which has been heated by the application of braking pressure can be subjected to cooling before the said part is again called upon to be subjected to heating by other of the pressure exerting means.

Further it will be appreciated that the annular space I6 between the annular braking surfaces III and admits of the circulation of cooling air which ensures the rapid dissipation of heat.

Moreover it will be appreciated that the brake is light in weight and that by arranging for the annular braking surfaces I0 and II to vbe axially displaceable the brake pads'IQa, |9b are able to exert pressure on both sides of the annular braking surfaces I0 and II.

The arrangement of the pressure exerting sleeves I8 is such that if relieved of all pressure the brake pads |9a, |9b can be readily removed for replacement purposes, said operation being facilitated by reason of the said brake pads being formed in two parts.

In the construction illustrated in Figure 3 the annuli III and I I are of a rectangular shape in cross section instead pf the truncated triangular shape of these parts as shown in Figure 2 and with the braking surfaces of the annulus Il constituting a continuation of the braking surfaces of the annulus l0. Further instead of employing envelopes 23 'with corrugated bottoms the sleeves I8 are enclosed by and gripped frictionally by envelopes 23 which are nonyielding in character but which also permit relative displacement between the sleeves I8 and members I1 to provide automatic adjustment to compensate for wear of the friction surfaces. A return spring 3|5 is located between the head of a pin ||5 and the head of pin IB. A sealing ring 2|! is provided between the head of the pin I! and the member I1. Between the `member |8a and the pin Ii'is provided a seal 22| and cover plate 222 held in place by a light spring 2l.

Otherwise the construction, arrangement and operation of the form of brake illustrated in Figure 3 is substantially the same as that illustrated in Figures 1 and 2.

In the construction illustrated in Figures 4 and 5 a three armed spider Il having three equidistantly spaced arms |4a again is employed and the inner periphery of the wheel 8 is provided apart axially. The outer and inner annuli of each set are spaced apart radially and adapted to pass through the space between the annuli are sleeves 21a within whichare disposed pins 28. The two sets of annuli III and II are spaced apart axially by brake pads |8a, ISb, |30. The innermost brake pads |9a abut end blocks 28 whilst the outer brake pads I9b abut the presented faces of the respective arms Ila. Each pin 21 is axially arranged land the headed outer end thereof is located vwithin an inwardly directed truncated recess I 8c in the centre of the head of a sleeve I8. The sleeves I8 each enclose a complementarily shaped block Ilb associated with the arms Ila of the spider I4 and a liquid proof seal between the blocks Mb and the sleeve |8 is obtained by means of sealing rings 2|. The spaces between the inner surfaces of the sleeves I8 and the blocks |4b are in communication by way of passages 29a with an annular passage 28 having a sealing ring 29| and connected to the fluid pipe lines by way of a nipple 30. Seals 22| are provided'between the pins 21, sleeves 26 and blocks Mb.

The assembly of annuli II) and II brake pads I9a, |9b, |90 and the sleeves I8 are held together by nuts 21h which are screwed on to the threaded inner ends of the pins 21 which extend through sleeves 21a. Thev nuts 2lb are locked so that there is freedom between the brake pads |8a, lsb, |9c and the annuli I0. when the hydraulic liquid is not under pressure.

Each hydraulic pressure applying means is provided with a passage 29h for bleeding purposes in known manner.

In this arrangement on application Aof braking pressure the uid pressure is transmitted through the pipelines by way of the nipple 30 into the annular passage 29 whence it is transmitted to the space between the sleeves I8 and the blocks Hb by way of the respective passages 29a. The braking pressure is then transmitted through the sleeves I8, pins 21, nuts 2lb and end blocks 28 to cause the brake pads |811, |811, IBc t0 apply braking pressure to the annuli I8 and II'.

Although in all of the constructions hereinbefore described the braking pressure has been applied at three equldistantly spaced positions it can be applied at one position only as is indi- 5 cated in Figure 6 or at two diametrically opposite positions as is illustrated in Figure '7 or at isolated positions at angles other than 180.

In the casel of the single application ShOWn in Figure 6 the hydraulic pressure applying system is carried by a single plate i4 which is bolted to the undercarriage leg I3 whilst in the construction illustrated in Figure 'I the two pressure applying systems are carried at the ends of a diametrically arranged plate I4 which again is bolted to the undercarriage leg i3 of the aircraft.

It will be understood that if preferred the braking pressure may be applied otherwise than hydraulically for example, pneumatically.

Although the invention has been described as applied to brakes for the landing wheels of aircraft it will be appreciated that the invention is also applicable to brakes for the wheels of other vehicles.

Having described my invention. what I claim is:

1. Brake apparatus which comprises an inner and an outer wheel bracket member, an inner and an outer brake disc secured to said inner and outer brackets respectively to permit a limited relative movement in an axial direction and having a circumferential space between the opposed edges of said discs, a stationary support having a pair of friction pads, said Vpads being on opposite sides of said brake discs, a guide stem secured to said Support and extending through Said circumferential space, a piston secured to the free end of said stem and a cylinder slidable thereon and acting against the face of one of' the pads of said pair, and means to admit pressure fluid between said piston and cylinder. K

2. The brake apparatus of claim l in which said support comprises a spider on which a plurality of' pairs of said pads are mounted on said spider in symmetrical relation.

3. The brake apparatus of claim 1 which coin-A prises a spring adapted to press said piston and cylinder apart.

4. Brake apparatus which comprises a Wheel,

inner and outer axially displaceable annular brake discs spaced radially apart and rotatable by said wheel, a pair of non-rotatable friction pads disposed on opposite sides of said discs, supporting means for said pads on opposite sides of said disc, said pads and supporting'means extending circumferentially over a minor proportion only of the discs, said pads being relatively displaceable in an axial direction, and fluid pressure operated mechanism to eiect said displacement and bring about frictional contact between the pads and the discs, said mechanism comprising a guide stem extending through the space between said discs and operatively connected to one of the pads of said pair, and fluid actuated elements, comprising a cylinder and a piston, relatively dis' placeable in an axial direction, one of said elements being connected to said guide stem and the other reacting against the other pad of said pair to press said pads against said discs.

5. Brake apparatus which comprises a wheel. inner and outer axially displaceable annular brake discs spaced radially apart and rotatable by said wheel, a pair of non-rotatable friction pads disposed on opposite sides of said discs and extending circumferentially over a minor proportion of the discs, said pads being relatively displaceable in an axial direction, and iuid pressure operated mechanism to effect said displacement and bring about frictional contact between the padsand the discs, said mechanism comprising a stationary support secured at one side of the discs and associated with one of said pads, a piston and cylinder device whereof the cylinder comprises a skirt portion and a base having an acting face operatively associated with the other of said pads, means to admit pressure duid between said piston and cylinder and a guide stem passing through the space between the discs having one end secured to said piston andthe other end secured to said stationary support.

6; Brake apparatus which comprises a wheel, inner and outer axially displaceable annular brake discs spaced radially apart and rotatable by said wheel, a pair of non-rotatable friction pads disposed on opposite sides of said discs and extending circumferentially over a minor proportion of the discs, said pads being relatively displaceable in an axial direction, and fluid pressure operated mechanism to effect said displacement and bring about frictional contact between the pads and the discs, said mechanism comprising a stationary support secured at one side of the discs and associated with one of said pads, a guide sleeve secured to said stationary support and passing through the space between the discs, a piston and cylinder device wherein the piston is secured to the stationary support and the cylinder comprises a base portion and a sleeve portion surrounding the piston, means to admit pressure fluid between the cylinder base and the piston, a pressure plate on the side of the discs remote from the piston and cylinder and a guide stem extending through the guide sleeve and associated with the cylinder and pressure plate, whereby on the admission of pressure duid to the cylinder axial displacement of the guide stem and pressure plate takes place thereby effecting frictional engagement between the pads and the discs.

7. Brake apparatus according to claim 4 which comprises a plurality of circumferentially spaced pairs of friction pads and uid pressure operated mechanisms.

8. Brake apparatus according to claim 5 which comprises a plurality of circumferentiallly spaced pairs of friction pads and fluid pressure operated mechanisms.

' HENRY JAMES BUTLER.

REFERENCES CITED The following references are of record in the le of this patent:

lUNITED STATES PATENTS Number Name Date 2,108,059 Glasner Feb. 15, 1938 2,274,885 Brown Mar. 3, 1942 2,319,231 Hawley May 18, 1943 2,351,041 Hawley June 13, 1944 2,366,093 Forbes Dec. 26, 1944 2,419,113 Bricker Apr. 15, 1947 

